And just to be clear before anyone gets defensive, i'm not saying that Jon's voice wasn't as GOOD as any of those other guys or that he wasn't as good a singer or whatever, i'm suggesting that objectively, he arguably didn't have such a strong organ physically to begin with.

On the first two records he has incredible range but not what i'd call strength or depth in the same way as e.g. Axl does on Appetite or Dickinson does anywhere. Jon had range and power but it was a relatively thin sound at the higher end.

For comparison, check Axl aged 48 in 2010 and see the power, range and rasp he still had at 1:45: